You Have a Twin!
by NorseAmongGreeks
Summary: The Crew of the Argo II is on its way to Rome, amazed that they, after proving how much of a fraud Octavian was, were able to unite the camps, as well as pull the Gods out of their split personality disorder. Percy was betrayed by both Luke and Annabeth, so she is not among the Seven, but they haven't found a replacement. First story. Flames will be thrown in the fireplace.
1. Who Is This Girl?

~~New Beginnings~~

Percy was sitting on the railing of the deck of the Argo II, staring at the ground as they flew to Topeka because of Piper's vision. He was thinking of Annabeth. The two happy couples aboard the Argo II made him think about when he dreamed of the two of them being a happy couple, the days before her betrayal. IN short, Percy was sulking, even if he was too proud to admit it.

Percy was snapped out of his thoughts by the sound of Leo calling his name. Percy looked up to see Leo waving at him to come over, acting as if something had freaked Leo out and he felt the need to share it with someone else. Percy jogged over to Leo, who looked up at him and spoke. "There is someone in an Iris Message who says that she needs to speak with you." Percy nodded, and walked in the direction Leo was pointing.

Sure enough there was an Iris Message waiting for him. And the sight waiting in the Iris Message was enough to make him scream.

~~LINE BREAK~~

Leo jumped when he heard Percy's scream. He sounded more surprised than scared, almost as if the last person he expected to see was in the Iris Message. It got him running, though. No matter how little he liked to admit it, he had a thing for a certain son of Poseidon.

Leo stopped next to Percy, and registered the look of shock and –happiness?- on Percy's face. He then turned to assess the person in the Iris Message. There was a girl in the center of the mist-screen. She had long, straight black hair, and a wide grin plastered on her face. Leo looked at her eyes, and shot back. They were electric blue, almost like Jason's, but there was more power behind them, and more danger. Leo was intimidated by her the same way he was by Percy. Danger and instability made him intrigued the same way that Percy did.

Leo walked out, figuring that neither Percy nor the girl would want him to be eavesdropping on their conversation from inside the room.

~~LINE BREAK~~

Percy was more that surprised to see the girl who was staring back at him from the Iris Message. Her electric blue eyes were gleaming with happiness at the sight of him, and even though he was slightly mad at the girl who was looking back at him. "Sup, bro?" she asked, and Percy just smiled.

This annoying, crazy, and at times straight up devious girl was not his full-blooded sister, but actually his half-sister through his mom. But he thought of her as a sister, even if they had only grown up together until they were five. She had sacrificed herself to save him and his mom, and had achieved Valhalla, the Norse version of Elysium. That's right, even though he was a Greek, his sister was a Nord, a completely separate pantheon. They were born as twins, but they had different father. While his dad was Poseidon, she was the daughter of three Norse Gods, created by them to serve as an intersection of good, bad, and the middle ground. She was the daughter of Frey, Thor, and Loki. But they were siblings before anything else, and she only returned once or twice every year from her trips between the worlds on missions for Odin, because she was one of the most powerful Einherjer, the warriors of Valhalla who were heroes in their past lives. But now she was back on Earth, or Midgard for her.

"Where are you?" Percy asked. She replied, "No hello? No how are you doing? No 'Mom and I were so worried'?" Percy smiled. Even when he was angry at her, she managed to make him smile and laugh. He shook his head, and the glared at her to give him an answer. "Well then. I'm on Olympus. Just got out of a meeting with your gods. They told me you guys are sort a demigod, and I thought you might need my help."

Percy turned serious all of a sudden. "This is a war of the Greek and Roman myths. What part of it entails the Nordic?" He asked. His sister's face mirrored his own, losing its joking appearance and becoming serious all of a sudden. She looked sad, almost, as if whatever it was, it spelled out certain doom for her. "Gaea had found herself a new partner in crime for making the rest of the world miserable. She's joined up with Hel." Percy was shocked. "Why?" He asked. "I don't know. She's probably trying to get either revenge on the Gods by destroying the realm that they get most of their army from or she's trying to start Ragnarok in a bid for power. Either that or she is out for revenge against the Gods through the destruction of humans, and, now that I'm here, me."

Percy nodded before another question came to him. "Now that you're here, are we going to have to fight Nordic monsters too?" He asked. He didn't know very much about Norse Mythology, but he was relatively certain that it was harder to attract the attention of Norse monsters than it was to attract the attention. "Not very much, unless we need to travel using Norse means." The girl replied. Percy accepted this as a valid answer. He looked the girl in the eyes and said, "When are you coming to the ship?" "Soon. Actually that was one of the main reasons why I called. Can you get me your coordinates?" She responded. He nodded and used his son of Poseidon powers to relay the coordinates to her. She nodded and smiled. "See you soon, brother." She said before swiping her hand through the screen, ending the Iris Message.

~~LINE BREAK~~

The Argo II's crew had organized on the deck, contemplating why Percy had been on the Iris Message for so long. Suddenly a roar sounded overhead. Heads snapped up to see a figure on what appeared to be a dragon. A girl jumped off, and landed, seemingly unarmed. Weapons were pointed at her, and Leo stepped forward, recognizing her from the Iris Message. "Who are you?" He asked.

"The name's Jackson, Echo Jackson."

 **AN**

 **Hello. I know, this is my first fanfic on . Echo is going to be my main OC for PJO Fanfics.**


	2. Echo

_"_ _Who are you?" He asked._

 _"_ _The name's Jackson, Echo Jackson."_

To say there was an uproar at her words would have been like saying that Gaea was only slightly power hungry. It was a massive understatement. Percy came out in the middle of the racket to find his sister standing in the middle of the chaos with a wicked grin on her face. For a second he could see the Loki in her, before the wicked grin turned into a real smile when she saw Percy. He rushed over to her through the chaos and hugged his twin. He realized that the deck had gone quiet with people watching them. Echo pulled away and beamed at him.

Percy was amazed. Echo was still as tall as he was. For whatever reason, they had always been the exact same height. Must be a Viking thing.

Percy was pulled back into reality by someone asking, "You know the strange girl who just invaded our ship?!" He turned around to find that it was Jason who had spoken. He nodded numbly, and, as usual, Echo jumped in. "Oh Percy knows me really well. I'm his twin sister. Well, technically twin half-sister. Well, more like twin quarter-sister. Well, it depends on how you look at it if you have four parents, but are called a demigod, only half god."

Percy's friends looked even more confused by her explanation, and Percy sighed. Echo was great and all, but she loved screwing people over by messing with their minds. "Echo, these are the other members of the Argo II's crew. Guys, this is Echo, my twin sister." "You have a twin?!" Hazel exclaimed. "Wait, what was the whole part about her being your half-twin and having four parents?" Leo asked.

"Well, Mr. Latino Elf, I am the biological daughter of Sally Jackson, Loki, Thor, and Frey. I was created as Percy's twin by Odin as a weapon and sort of super-soldier," Echo responded. All of the crew looked stunned by her answer. Jason was the first to snap out of his stupor to ask, "So the Norse Gods are real too?" "You bet. And that's part of the reason why I'm here. You see, the Norse god Hel has decided to partner up with Gaea to end your gods and this planet. And I was sent to help you guys fight her and all the Norse monsters she will probably send after you," Echo responded.

"You, are going to protect us?" Frank asked. Echo turned around to stare him straight in the eye, and began to speak. "Listen, Frank Zhang, son of Emily Zhang and Mars Ultor, and remember what I tell you. I may not look like much, and I may make a lot of jokes, but I am the daughter of three Gods, and I have inherited their powers. I am an Einherjer, a servant of Odin, and a dangerous enemy. I have travelled the nine realms, defeated many giants and monsters, died and came back to life, and rebound Fenrir Wolf. I am a dangerous enemy, so do not make me one. Do you understand?"

Frank nodded, a terrified expression on his face. Well, Echo was definitely a force to be reckoned with.


End file.
